To promote the efficient preparation and utilization of Chinese yam polysaccharides, an extraction process of Chinese yam polysaccharides with ultrahigh pressure combined with microbial fermentation was established, and the enzyme inhibitory activity of Chinese yam polysaccharide was investigated in this study. With fresh yam as raw material, from nine different strains, Lactiplantibacillus plantarum subsp. plantarum were selected as the subsequent fermentation strains. Based on the single factor experiment, the L18(37) orthogonal table design was used to optimize the ultrahigh pressure and lactic acid bacteria fermentation collaborative extraction process of yam polysaccharide to determine the optimal extraction conditions: inoculation concentration 5%, fermentation time 2 days, solid-liquid ratio 1:5 (m/V), extraction pressure 500 MPa, holding time 10 min. With these conditions, the extraction yield of polysaccharides was 9.23% and the obtained polysaccharides exhibited significant α-amylase inhibitory activities (7.48 mg•mL−1) and pancreatic lipase inhibitory activities (7.07 mg•mL−1). The results showed that ultrahigh pressure combined with lactic acid bacteria had the potential to produce Chinese yam polysaccharide with high yield and enzyme inhibitory activity. This study can provide a way for the development and utilization of Chinese yam.